Device for sharpening drills



April 6, 194 8. J. PERKINS- DEVICE FOR SHARPENING DRILLS- Filed NOV. 30, 1944 2 Sheets-Sheet 1 1 I I I f r Per]: 612/6 April a, 1948]. J.PERK1N$ ,2,Is9*,144-

DEVICE FOR SHARPENING DRILLS Filed Nov. 30, 1944 2 sheets-shed 2 Z11/v elvtor RD]: biz/s Patented Apr. 6, 1948 UNITED "STATES QFJF-l DEVICE i on ram Application November 30, 1944; Serial No. 565,945

InfireatBritain June 15, 1944 This invention relates .to the sharpening of small fluted drills.

The main object of the present inventionis to provide simple devices for enabling small drills to be sharpenedlby hand even by unskilled persons.

A fur her object is to-provide adevice whereby both cutting edges of a small drill-maybe sharpened with a single setting-upof the drill in the device.

The invention consists in brief in a small drillsharpening device comprising a drill holder having drill-locating means 'and drill-clamping means for holding .a drillin fixed position with its .end suitably presented simultaneously to a pair of planes inclined to the axis, of thedrilLsaid planes eomprisingmeans on the holder for guiding a hand-manipulated sharpening stone or the like.

The inventionalso consists inadril-l-sharpening device as set forth in the preceding paragraph, wherein said drill-locating means comprises a -V groove or like abutment surface, a spring-urged clamping jaw and a spring-urged plunger preferably mounted on an adjustable carriage, the end of said plunger beinguadapted to engage a flute in a drill to besharpe'ned.

The invention also consists ina drill-sharpening device as set forth in either of the two preceding paragraphs, wherein said drillclamping means comprise a clamping jaw and positive means for urging said jawtowards a drill abutment surface.

Th in eni sna s .cqns st fi a l sharpe ing device as set forth in any of the three pree ceding paragraphs, wherein said holder comprises an inverted V-shaped block, the intersecting surfaces of which comprise the two intersecting planes referred to.

The invention also consists in a drill-sharpening device as set forth in the preceding paragraph, wherein said surfaces are provided with hard inserts, e. g, of tungsten carbide.

The invention also consists in a drill-sharpening device as set forth in the first of the two preceding paragraphs, wherein rollers are provided let into said surfaces for the purposes described hereinafter.

The invention also consists in a drill-sharpening device as set forth in any of the six preceding paragraphs, wherein means are provided for axially locating a drill prior to sharpening thereof.

The invention also consists in a drill-sharpening device as set forth in the preceding paragraph, wherein said means comprise a rigid arm 3 Claims. (oral-219) pivoted on said holder and furnished at itsfree end with an adjustable screw orthe like.

The invention also consists in a drill-sharpening device substantially as hereinafter described withreference tothe accompanying drawings.

lEeferring ;to the accompanying diagrammatic drawings Fi g ure l-is a vertical longitudinal sectional-view of a convenient construction of drill sharpener embodying thepresent invention.

'Figurefizis an inverted plan view-thereof.

Figure?) is a'planviewof part thereof.

Figure 4 is a-verticallongitudinal sectional view of part'of the device showing-a drill in position for sharpening,

Figure 5-is an end-view of the device f Figure'Sis an en-largedplan view of part ofthe sharpener with a drill in position, and

Figure -;'7 is an enlarged invert-ed plan view of the deviceshowninFigure 6.

In carrying-the-invention into effect accordingto one convenientforrnillustrated byway of example in Figures 1-5, I -provide-a bloc'kofsteel 'a-w'hich in end vi'ew is of polygonal N form, the base of-the block being about\1 /4 in width and about 4" in-length. The intersectingv surfaces b of-the lo'lockare mutuallyinclined at an angle of about ':82 and the ridge formed-by the timersection-of the surfaces stands about 1" above the base 0 of-the-block. Theends ofthe block lie in planes at right angles to the ridgeland one of :theseends cl is providedwitha V groove elextending vertically from the ridge to .the :base of the block, :the groove being of suificientdepth to enable +anytwist drill up to a diameter of, say, 3%" to rest snugly therein.

A hole is drilled longitudinally through about the centre of the block to accommodate a rod 1 carrying at one end a pivoted jaw g, the other end being screw-threaded to receive a knurled knob h internally screw-threaded.

The jaw is provided with a V-grooved face so that when the rod 1 is passed through the hole and screwed tight, the groove in the face of the jaw abuts a drill 2' and the jaw holds the drill rigidly in the V groove e.

The rod f is furnished with a light helical spring 1 serving to urge the jaw lightly towards the V groove e.

A pair of locating pins Iclc are fixed to the block to maintain the jaw substantially opposite the groove e. This end (I of the block is also furnished with an annular member m the semi-circular extension portion of which is provided with a curved slot n radiused approximately about the centre of the groove e and mounted on this extension piece is a carriage having a clamping screw 12 passing through the curved slot 1%.

The carriage embodies a spring-urged plunger q set at an angle of about 30 to the horizontal, i. e., to the line of the ridge, the chisel-shaped end 1 of the plunger being suificiently fine to enable it to bear against the edges of a flute of the smallest drill intended to be sharpened by means of the device.

The angle of the carriage to the plane of the. adjacent end of the block may be varied by slackening the clamping screw 21, moving the carriage and retightening; suitable markings may be placed on the carriage and on the semi-circular extension portion of the member an to assist in setting the carriage.

A rigid arm s is provided pivoted on the block, the arm being furnished at its free end with a screw 15 and locknut u whereby a drill may be set in position with its end resting against the head 0 of the screw t and projecting above the V surface planes bb to a predetermined extent.

In order to sharpen a twist drill i it is passed upwards between the V groove e and V clamping jaw g, the knurled knob it having been loosened and thrust endwise to overcome the light helical spring 7'. The pivoted arm 3 carrying the screw is moved into position over the upper end of the groove 2 and the drill arrested thereby. The end 1" of the spring-urged plunger during this operation is allowed to bear against a flute of the drill by slackening the knurled nut 10, thus ensuring that the drill is correctly presented to the planes of the intersecting V surfaces. The knurled knob h is now tightened, the pivoted arm s swung clear and the nut w tightened to retract the plunger q; finally the fiat face of a sharpening stone (not shown) is applied to one.

V face I). The stone may now be moved backwards and forwards by hand in contact with the V face, and in contact with the projecting tip of the drill and when this projectin portion has thus been ground away to the full extent permitted, the sharpening stone is then similarly applied to and operated in conjunction with the other face b. The sharpened drill is then removed from the holder by first slackening the knurled knob h and then withdrawing the drill downwards,

By this means both cutting faces of the drill are sharpened, the correct backing-off angle lying usually between about 5 and 10 being determined by the pre-set angle of the spring plunger carriage o.

The swinging arm s for axial location of a drill to be sharpened may be dispensed with if desired. Also, it is not essential to employ two intersecting surfaces but if only one beemployed then it is necessary to re-set each drill to be sharpened by rotating it through after one of its cutting faces has been sharpened.

In order to resist wear of the surface or surfaces b guiding the sharpening stone, these surfaces may be formed of or provided with inserts of highly resistant material, e. g. case hardened steel or tungsten carbide.

' I claim:

'1. A small drill-sharpening device comprising a drill holder having means for laterally locating a drill in relation thereto and drill-clamping means for holding said drill in fixed position with secting surfaces of which comprise guiding surfaces for co-action with said sharpening stone.

3. A drill sharpening device as claimed in claim 1 including an adjustable drill-point-abutment member pivotally mounted on said device for axially locating said drill prior to securing it by said clamping means.

- JOHN PERKINS.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date' 201, 49 Rider Mar. 19, 1878 a 352,789 Thomason Nov. 16, 1886 1,195,440 Campbell Aug. 22, 1916 1,293,751 Garrison Feb. 11, 1919 1,545,574 Rollins July 14, 1925 1,582,014 Kendall Apr. 20; 1926 FOREIGN PATENTS Number Country Date 608,786 France Apr. 30, 1926 

